190
chapter 11
Heteropolysaccharides II: Proteoglycans and Peptidoglycans
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acetyl transferase
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FIGURE 11-11
Stepwise degradation of heparan sulfate. The deficiency diseases
corresponding to the numbered reactions are: I = mucopolysaccharidosis
(MPS) II, Hunter’s syndrome; 2 = MPS I, Hurler’s, Scheie’s, and
Hurler-Scheie’s syndromes; 3 = MPS III A, Sanfilippo’s syndrome type
A; 4 = MPS III C, Sanfilippo’s syndrome type C; 5 = MPS III B,
Sanfilippo’s syndrome type B;
6
= no deficiency disease yet known; 7 =
MPS VII, Sly’s syndrome;
8
= MPS III D, Sanfilippo’s syndrome type D.
The schematic drawing depicts all structures known to occur within
heparan sulfate and does not imply that they occur stoichiometrically. Very
few of the glucuronic acid residues are sulfated. [Reproduced with
permission from E. F. Neufeld and J. Muenzer. In:
M e ta b o lic B a sis o f
In h e rite d D isea se,
7th ed., C. R. Scriver, A. L. Beaudet, W. S. Sly, and
D. Valle (Eds). McGraw-Hill, New York, 1995, p. 2468.]
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COOH
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N-acetylgalactosamine
^ д с
4-sulfatase
I
3
■etc
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(3-hexosaminidase
4
A, В
COOH
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(3-glucuronidase
etc
•etc
FIGURE 11-12
Stepwise degradation of dermatan sulfate. The deficiency diseases
corresponding to the numbered reactions are: I = MPS II, Hunter’s
syndrome; 2 = MPS I, Hurler’s, Scheie’s, and Hurler-Scheie’s
syndromes; 3 = MPS VI, Maroteaux-Lamy syndrome; 4 = Sandhoff’s
disease; and 5 = MPS VII, Sly’s syndrome. This schematic drawing
depicts all structures known to occur within dermatan sulfate and does
not imply that they occur in equal proportion. For instance, only a few of
the L-iduronic acid residues are sulfated, and L-iduronic acid occurs
much more frequently than glucuronic acid. [Reproduced with
permission from E. F. Neufeld and J. Muenzer. In:
M eta b o lic B asis o f
In h e rite d D isea se,
7th ed., C. R. Scriver, A. L. Beaudet, W. S. Sly, and
D. Valle (Eds). McGraw-Hill, New York, 1995, p. 2467.]
hypotonic environment. The contents of a bacterium can
exert an osmotic pressure as high as 20 atm. At cell divi-
sion, the walls rupture and reseal rapidly.
Bacteria are classified into two groups on the basis of
a staining reaction discovered by Gram in 1884. In this
reaction, the cells do or do not retain a crystal violet-
iodine dye complex after an alcohol wash. Cells that retain
the stain are gram-positive; those that do not are gram-
negative. This empirical classification divides bacteria into
two classes that differ in cell wall structure.
Gram-positive bacteria (e.g.,
Staphylococcus aureus)
are surrounded by a cytoplasmic membrane with a bilayer
